Cisco 10000 Series Configuration Manual page 281

Chapter 14 1-Port OC-48/STM-16 Packet over SONET Line Card Configuration
Other Configuration Commands
line loops packets received from the line back onto the line at the line card level without being processed
in the Route Processor.
Use the no form of the command to stop the loopback test.
For more information on loopbacks, refer to the online Cisco 10000 Series Internet Router
Troubleshooting Guide.
In the following example, a loopback is set for the 1-Port OC-48/STM-16 Packet over SONET line card
in slot 5:
Router(config)# interface pos 5/0/0
Router(config-if)# loopback line
Cisco 10000 Series Router Line Card Configuaration Guide
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